Engine Knock

Greg · December 16, 2003

I have a Buick LeSabre rental car while the dealer does some mods on my CTS. The 3.8 in this Buick has a loud engine knock on startup that neither of my vehicles with a 5.3 could touch.

thecraft · September 11, 2006

1995 C1500 with 350, still no knock after 156k miles!

Matt99Z71 · September 12, 2006

1999 Silverado Z71 5.3

113k miles

Mine knocks for 10-15 seconds with greater intensity the colder it is outside. It won't do it at all during the summer. It doesn't bother me, I don't really put it under a load until it goes away. I'd rather it didn't do it, but it burns no oil, I don't get any "puffs" of smoke when it starts up so its okay. I use only mobil 10w-30. I love this truck.

Green_Monster · September 16, 2006

No knock.

2006 1500 CC 4X4 5.3 24,000 miles

I haven't driven the truck in cold weather yet. I have only had it since May 30th.

nitro882 · September 17, 2006

I have 14k on my 06 5.3l HO alum block with no knock wt all. All is quiet on startup.

I run 5w30 amsoil asl full synthetic in it.

Nappers · September 18, 2006

2000 GMC Yukon, 2WD, 5.3 bought with 68,000 had slight tick at start up, ran synthetic after purchasing, run Mobil 1 5/30, no knock at all, have 104,000 on it now.

Aaron

Greg · September 25, 2006

Got this e-mail today from a buddy of mine looking at a 2000 Yukon XL:

"Lansing dealer claims that only the 6.0L had the piston slap on cold start...sez 5.3 was not subject to that issue. Can you vet his remarks?"

I pointed him here to set him straight. Dealers!

saltwater_addict · September 25, 2006

does anyone know the name of the fluid you add with your oil change to sometimes quiet the top end i think it starts with an r not seafoam, this you actually keep for the full 3000 miles ribosone? im thinking of trying it i get the knock sometimes more than other times 170,XXX+

Greg · September 25, 2006

Before an oil change, I usually run a tank that's been treated with Techron. Thanks for the reminder.

jojiboy · September 26, 2006

does anyone know the name of the fluid you add with your oil change to sometimes quiet the top end i think it starts with an r not seafoam, this you actually keep for the full 3000 miles ribosone? im thinking of trying it i get the knock sometimes more than other times 170,XXX+

<{POST_SNAPBACK}>

Are you thinking of Rislone?

saltwater_addict · September 26, 2006

Yes i believe that is it thanks for the help im thinking of trying next time maybe clear it up alittle but if that doesnt work i guess ill just get things adjusted up there

05AZgmc · October 2, 2006

I have a 2005 WT gmc seirra ext cab 4x4 5.3L with an aluminum block(heard its kinda rare) with 43k miles( i think i can hear mine more cause of the alum. block), knocked since i bought, its pretty intermintent. but does it whenever it wants, sometimes on start up, sometimes after a long free way run, sometimes just normal operating temp. driving. In park or neutral it has a little stumble or shake at idle unless the a/c is on or its in drive(a load on the engine). I donno, bothers me, but not much i can do about it, ive been told by numerous dealerships and past GM techs(now my instructors) at school(UTI), that it is normal and they will run forever like that. so i will just try to ignore it, even tho its hard sometimes. Still runs great, and i hardly consume any oil, this oil change period it seemed to use maybe a little less than half quart, or maybe i was not level when i checked it. My worst problem with my truck is the alingment and "beam shake", other the that its fine... love it.

oh and the clunk on take off and some shifts from the rear diff, that bugs too. oh well, nothings perfect, even tho i wish it was...

HotRodCarts · October 4, 2006

2004 2500HD W/T 6.0L - 3500 miles.

No knock at all on cold starts but after engine is warmed up if I shut it off for 30 minutes to 2 hours and start it I get some lifter noise. I'm taking it to the dealer Monday to see what they tell me.

sleepur606 · October 5, 2006

2002 6.0L 2500HD 2WD +/- 86,500 miles

I've got it, and I envy all you people who don't. I'm not talking about a loud knock or piston slap, it's that damned annoying little knock you just barely hear coming from the engine compartment.

I looked for TSBs on the problem and only found one, the oil pump pickup o-ring. If you have a 4x4 and have the knock and want to try the remedy, first: it only works for about 2 seconds, second: don't, pulling the oil pan on the 2WD is pain enough.

I don't understand how GM can let this happen in their vehicles and then charge $5 or more for the part to "fix" it and then it doesn't last. I replaced the o-ring on mine with a new one from the local dealer, put it in, got everything back together, started the truck and sounded fine, turned it off and started it again...knock was back.

WTF GM!